Anode, secondary battery including the same, and the method of making anode

ABSTRACT

Alkali metal secondary batteries that include anodes constructed from alkali metal foil applied to only one side of a porous current collector metal foil. Openings in the porous current collectors permit alkali metal accessibility on both sides of the anode structure. Such anode constructions enable the utilization of lower-cost and more commonly available alkali metal foil thickness, while still achieving high cell cycle life at a significantly reduced cost. Aspects of the present disclosure also include batteries with porous current collectors having increased volumetric and gravimetric energy densities, and methods of manufacturing anodes with porous current collectors.

RELATED APPLICATION DATA

This application is a divisional of U.S. Nonprovisional patentapplication Ser. No. 16,803,286, filed on Feb. 27, 2020, entitled“Anodes For Secondary Batteries, And Secondary Batteries Including SuchAnodes”; which application claims the benefit of priority of U.S.Provisional Patent Application Ser. No. 62/812,454, filed Mar. 1, 2019,and titled Method of Making Perforated Current Collector Using CarrierFilm for Secondary Lithium Battery; U.S. Provisional Patent ApplicationSer. No. 62/833,487, filed Apr. 12, 2019, and titled Method of MakingPerforated Current Collector Using Carrier Film for Secondary LithiumBattery; U.S. Provisional Patent Application Ser. No. 62/812,398, filedMar. 1, 2019, and titled Perforated Current Collector Design for LithiumMetal Anode and Secondary Battery Containing the Same; U.S. ProvisionalPatent Application Ser. No. 62/833,495, filed Apr. 12, 2019, and titledPerforated Current Collector Design for Lithium Metal Anode andSecondary Battery Containing the Same; U.S. Provisional PatentApplication Ser. No. 62/812,482, filed Mar. 1, 2019, and titledPerforated Current Collector Made Via Photo-Lithography for SecondaryLithium Battery; U.S. Provisional Patent Application Ser. No.62/833,499, filed Apr. 12, 2019, and titled Perforated Current CollectorMade Via Photo-Lithography for Secondary Lithium Battery; U.S.Provisional Patent Application Ser. No. 62/812,441, filed Mar. 1, 2019,and titled Method of Making Perforated Current Collector Using aPerforated Carrier Film for Back-Side Lithium Extrusion andPlanarization for Secondary Lithium Battery; U.S. Provisional PatentApplication Ser. No. 62/833,500, filed Apr. 12, 2019, and titled Methodof Making Perforated Current Collector Using a Perforated Carrier Filmfor Back-Side Lithium Extrusion and Planarization for Secondary LithiumBattery; U.S. Provisional Patent Application Ser. No. 62/812,302, filedMar. 1, 2019, and titled Large Format Anodes For Secondary LithiumBatteries; U.S. Provisional Patent Application Ser. No. 62/833,501,filed Apr. 12, 2019, and titled Large Format Anodes For SecondaryLithium Batteries; U.S. Provisional Patent Application Ser. No.62/833,507, filed Apr. 12, 2019, and titled Large Format Anodes ForSecondary Lithium Batteries. Each of these applications is incorporatedby reference herein in their entirety.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to the field of anodes forsecondary batteries. In particular, the present disclosure is directedto alkali metal anodes with porous current collectors, secondarybatteries containing the same and methods of manufacturing the same.

BACKGROUND

Secondary (also referred to as rechargeable) lithium metal batteriesprovide great promise for the next generation of energy storage devicesdue to the significantly higher energy density they provide. Unlikeconventional lithium ion batteries, which contain anodes (also referredto as negative electrodes) formed from an intercalant material, such asgraphite, lithium metal battery anodes are formed from lithium metal,for example, thin sheets of lithium metal foil coupled to currentcollectors. The intercalation anodes of lithium ion batteries onlyprovide host structures for lithium ions and do not contribute to energystorage. Lithium metal battery anodes, by contrast, are formed, in part,by lithium metal, which contributes to energy storage, therebysignificantly increasing volumetric and gravimetric energy density.During charging and discharging cycles of a lithium metal battery,lithium metal is deposited onto the anode during charge and strippedfrom the anode during discharge.

The anode of a secondary lithium battery typically contains a lithiumfoil applied to both sides of a copper foil current collector. Testinghas shown that performance of the battery tends to improve as thethickness of the lithium foil is decreased, for example, cell cycle lifetends to optimize, and volumetric and gravimetric energy density tend toincrease, as the thickness of the lithium foil is decreased, forexample, to a thickness of lithium foil on each side of the currentcollector of less than or equal to approximately 20 um. However, it ischallenging to economically produce such thin layers of lithium foilwith currently available lithium foil manufacturing processes, such asby traditional roll-milling processes, and it is particularlychallenging to produce wider rolls, for example, greater than 55 mmwidths. With traditional roll-milling processes, the relatively soft andreactive nature of lithium results in low yield and, consequently highcost, to manufacture extremely thin lithium metal foil, e.g., athickness of less than or equal to approximately 10-20 um. Themanufacturing challenges also restrict the maximum available width ofextremely thin lithium metal foil, which in turn limits the arealdimensions of secondary lithium metal battery cells that can beproduced, thereby limiting the energy capacity of the cell.

SUMMARY OF THE DISCLOSURE

In an implementation, the present disclosure is directed to a method ofmanufacturing an anode, including receiving an alkali metal foil;receiving a porous current collector foil having first and secondopposing sides and a webbed structure defining openings each having avolume; and laminating the alkali metal foil and porous currentcollector foil together at the first side of the porous currentcollector, wherein the laminating includes forming extruded portions ofthe alkali metal foil that extend through the openings from the firstside to the second side and that substantially fill the volumes of theopenings.

In one or more embodiments of the method, the laminating step includescompletely filling the volumes with the extruded portions.

In one or more embodiments of the method, the laminating step includesextending the extruded portions until they are at least substantiallyflush with the second side of the porous current collector foil.

In one or more embodiments of the method, the openings in the porouscurrent collector foil define a percent open area that is greater than80%.

In one or more embodiments of the method, the openings in the porouscurrent collector foil define a percent open area that is greater than60%.

In one or more embodiments of the method, the openings in the porouscurrent collector foil define a percent open area that is greater than40%.

In one or more embodiments of the method, the openings have a maximumwidth that is greater than 0.5 mm.

In one or more embodiments of the method, the openings have a circularor polygon shape and are in a close packed arrangement.

In one or more embodiments of the method, a thickness of the currentcollector foil is from 4 um to 20 um.

In one or more embodiments of the method, the webbed structure of theporous current collector has a minimum web width extending betweenadjacent ones of the openings, wherein the minimum web width is lessthan 1 mm.

In one or more embodiments of the method, the webbed structure of theporous current collector has a minimum web width extending betweenadjacent ones of the openings, wherein the minimum web width is lessthan 0.25 mm.

In one or more embodiments of the method, the webbed structure of theporous current collector has a minimum web width extending betweenadjacent ones of the openings, wherein the minimum web width is lessthan 0.15 mm.

In one or more embodiments of the method, forming the openings in thecurrent collector using one or more of a perforating process, a rotaryhole punch process, a rotary die process, a rotary kiss-cut process, aphotolithography process, a photoetching process, an electroformingprocess, a laser cutting process, and a metal mesh weaving process.

In one or more embodiments of the method, coating the second side of thecurrent collector with an alkali metal coating.

In one or more embodiments of the method, the step of coating includesone or more of vapor deposition, electrodeposition, slot-die coating,dip coating, micro gravure, flexography, or plating during initialcharging of a cell containing the anode.

In one or more embodiments of the method, alkali metal foil is laminatedto only one side of the current collector metal foil.

In one or more embodiments of the method, the alkali metal foil has athickness in the range of 1 um to 1000 um.

In one or more embodiments of the method, the alkali metal foil has awidth that is greater than 55 mm.

In one or more embodiments of the method, the laminating step includeslaminating a plurality of rows of the alkali metal foil in aclosely-spaced parallel arrangement across the porous current collectorfoil to form a wide-format anode having a width in the range of 55 mm to300 mm.

In one or more embodiments of the method, the alkali metal foil is afirst alkali metal foil, the method further comprising laminating asecond alkali metal foil and the porous current collector foil togetherat the second side of the porous current collector.

In some aspects, the present disclosure is directed to a method ofmanufacturing an anode, including receiving at least one carrier film, acurrent collector metal foil having first and second opposing sides, andan alkali metal foil; laminating the at least one carrier film to thesecond side of the current collector metal foil to form a carrierfilm-current collector foil laminate; forming a plurality of openings inthe carrier film-current collector foil laminate to form a porouscarrier film-current collector foil laminate; laminating the alkalimetal foil to the first side of the current collector metal foil,wherein the laminating the alkali metal foil includes forming extrudedportions of the alkali metal foil that extend through the openings.

In one or more embodiments of the method, the plurality of openings eachdefine a volume, further wherein the step of laminating the alkali metalfoil to the first side of the current collector metal foil includescompletely filling the volumes with the extruded portions.

In one or more embodiments of the method, the step of laminating thealkali metal foil to the first side of the current collector metal foilincludes extending the extruded portions until they are at leastsubstantially flush with the second side of the current collector metalfoil.

In one or more embodiments of the method, the step of laminating thealkali metal foil includes extending the extruded portions through anentire thickness of the current collector metal foil and through atleast a portion of a thickness of the at least one carrier film.

In one or more embodiments of the method, the at least one carrier filmhas a first side contacting the current collector metal foil and asecond opposing side, wherein the step of laminating the alkali metalfoil includes extending the extruded portions until ends of the extrudedportions are substantially flush with the second side of the at leastone carrier film.

In one or more embodiments of the method, the alkali metal foil is afirst alkali metal foil, the method further including delaminating theat least one carrier film from the current collector metal foil; andlaminating a second alkali metal foil to the second side of the currentcollector metal foil.

In one or more embodiments of the method, delaminating the at least onecarrier film from the current collector metal foil leaving the extrudedportions standing proud of the second side of the current collector.

In one or more embodiments of the method, planarizing the extrudedportions across the second side of the porous current collector.

In one or more embodiments of the method, determining an extent ofplanarization of the extruded portions with a planarization monitoringsystem.

In one or more embodiments of the method, generating a planarizationfeedback signal according to the determined extent of planarization andsending the planarization feedback signal to a planarizing system tocontrol an extent of the planarization.

In one or more embodiments of the method, the step of determining anextent of planarization includes execution of a machine vision algorithmconfigured to process images of the porous current collector todetermine an extent of planarization of the extruded portions.

In one or more embodiments of the method, applying pressure to theextruded portions to reduce a height of the extruded portions anddistribute the extruded portions across the second side of the porouscurrent collector.

In one or more embodiments of the method, the at least one carrier filmhas a thickness that is selected to result in a target height of theextruded portions, the target height designed and configured for atarget thickness and/or volume of the alkali metal on the second side ofthe current collector.

In one or more embodiments of the method, the at least one carrier filmincludes a first and second carrier film, wherein the step of formingthe plurality of openings includes forming openings that extend througha thickness of the current collector metal foil and first carrier film,but that do not extend through the second carrier film.

In one or more embodiments of the method, delaminating the secondcarrier film prior to the step of laminating the alkali metal foil.

In one or more embodiments of the method, the delaminating step includesremoving waste with the second carrier film, the waste created duringthe step of forming a plurality of openings.

In one or more embodiments of the method, applying an alkali metalcoating to the second side of the current collector foil.

In one or more embodiments of the method, the step of applying an alkalimetal coating includes one or more of vapor deposition,electrodeposition, slot-die coating, dip coating, micro gravure,flexography, or plating during initial charging of a cell containing theanode.

In one or more embodiments of the method, alkali metal foil is laminatedto only one side of the current collector metal foil.

In one or more embodiments of the method, forming the openings in thecurrent collector using one or more of a perforating process and arotary die process.

In one or more embodiments of the method, the alkali metal foil has athickness in the range of 1 um to 1000 um.

In one or more embodiments of the method, the alkali metal foil has awidth that is greater than 55 mm.

In one or more embodiments of the method, the step of laminating thealkali metal foil includes laminating a plurality of rows of the alkalimetal foil in a closely-spaced parallel arrangement across the porouscurrent collector foil to form a wide-format anode having a width in therange of 55 mm to 300 mm.

In one or more embodiments of the method, determining an extent ofextrusion of the alkali metal with an extrusion monitoring system.

In one or more embodiments of the method, generating an extrusionfeedback signal according to the determined extent of extrusion andsending the extrusion feedback signal to a laminating roller set tocontrol an extent of the extrusion.

In one or more embodiments of the method, the step of determining anextent of extrusion includes execution of a machine vision algorithmconfigured to process images of the at least one carrier film todetermine an extent of extrusion of the extruded portions.

In one or more embodiments of the method, a thickness of the at leastone carrier film is from 13 um to 300 um.

In some aspects, the present disclosure is directed to a method ofmanufacturing a lithium metal anode. The method includes receiving amulti-layer substrate that includes a current collector foil layer andat least one additional layer; applying a hole forming process to themulti-layer substrate to form a plurality of holes that extend throughthe current collector foil and at least partially through the at leastone additional layer; laminating an alkali metal foil to a first side ofthe current collector foil; extruding the alkali metal foil through theholes to form a plurality of extruded portions of the alkali metal foilthat extend at least partially through the at least one layer; andremoving the at least one additional layer.

In one or more embodiments of the method, applying pressure to theextruded portions to distribute the extruded portions across a secondside of the current collector.

In some aspects, the present disclosure is directed to a method ofmanufacturing an alkali metal anode. The method includes laminating analkali metal foil to a first side of a porous current collector, thecurrent collector having a plurality of holes that extend from the firstside to a second opposing side of the current collector; extruding thealkali metal foil through the holes in the current collector to formextruded portions of the alkali metal, wherein the extruded portionsextend at least to the second side and substantially fill the holes.

In one or more embodiments of the method, the alkali metal foil is afirst alkali metal foil, the method further comprising laminating asecond alkali metal foil to the second side of the porous currentcollector.

In one or more embodiments of the method, the holes in the porouscurrent collector define a percent open area that is greater than 80%.

In one or more embodiments of the method, the holes in the porouscurrent collector define a percent open area that is greater than 60%.

In one or more embodiments of the method, the holes in the porouscurrent collector define a percent open area that is greater than 40%.

In one or more embodiments of the method, the holes have a maximum widththat is greater than 0.5 mm.

In one or more embodiments of the method, the holes have a circular orpolygon shape and are in a close packed arrangement.

In one or more embodiments of the method, a thickness of the currentcollector is from 4 um to 20 um.

In some aspects, the present disclosure is directed to a secondarybattery, including an alkali metal anode, a cathode, and a separator;wherein the alkali metal anode was manufactured according to any of theforegoing embodiments.

In some aspects, the present disclosure is directed to a porous currentcollector metal foil for use with an alkali metal battery anode. Thecurrent collector includes first and second opposite sides and a webbedstructure defining a plurality of openings extending between the firstand second sides, wherein a percent open area defined by the pluralityof openings is greater than 40% and the openings each have a width thatis greater than 0.5 mm.

In one or more embodiments of the current collector, the webbedstructure has a substantially uniform width.

In one or more embodiments of the current collector, the webbedstructure is designed and configured to maximize the availability at thefirst side of an alkali metal foil laminated to the second side.

In one or more embodiments of the current collector, the webbedstructure is designed and configured to maximize a uniformity ofconsumption of an alkali metal foil laminated to only one side of thecurrent collector.

In some aspects, the present disclosure is directed to an anode for analkali metal secondary battery, including a porous current collectorfoil having first and second opposing sides and a webbed structuredefining openings each having a volume; and an alkali metal foillaminated to only one side of the porous current collector foil, whereinportions of the alkali metal foil extend through the openings from thefirst side to the second side and substantially fill the volumes of theopenings.

In one or more embodiments of the anode, the openings in the porouscurrent collector foil define a percent open area that is greater than40%.

In one or more embodiments of the anode, the openings in the porouscurrent collector foil define a percent open area that is from 80% to90%.

In one or more embodiments of the anode, the openings have a width from0.5 mm to 1.5 mm.

In one or more embodiments of the anode, the webbed structure of theporous current collector has a minimum web width extending betweenadjacent ones of the openings, wherein the minimum web width is lessthan 1 mm.

In one or more embodiments of the anode, the webbed structure of theporous current collector has a minimum web width extending betweenadjacent ones of the openings, wherein the minimum web width is lessthan 0.25 mm.

In one or more embodiments of the anode, the webbed structure of theporous current collector has a minimum web width extending betweenadjacent ones of the openings, wherein the minimum web width is lessthan 0.15 mm.

In one or more embodiments of the anode, the alkali metal foil has athickness between 1 um and 1000 um.

In one or more embodiments of the anode, the alkali metal foil has awidth that is greater than 55 mm.

In one or more embodiments of the anode, the anode includes a pluralityof rows of the alkali metal foil positioned in a closely-spaced parallelarrangement across the porous current collector foil, wherein a width ofthe anode is between 55 mm to 300 mm.

In one or more embodiments of the anode, the alkali metal foil islaminated to the first side of the porous current collector foil,wherein extruded and planarized portions of the alkali metal foil aredistributed along the second side of the porous current collector foil.

In one or more embodiments of the anode, the alkali metal foil islaminated to the first side of the porous current collector foil,further wherein the second side of the porous current collector foilincludes a coating of the alkali metal.

In one or more embodiments of the anode, the coating was formed by oneor more of vapor deposition, electrodeposition, slot-die coating, dipcoating, micro gravure, flexography, or plating during initial chargingof a cell containing the anode.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the disclosure, the drawings showaspects of one or more embodiments of the disclosure. However, it shouldbe understood that the present disclosure is not limited to the precisearrangements and instrumentalities shown in the drawings, wherein:

FIG. 1 illustrates one example of a cell of a secondary alkali metalbattery;

FIG. 2 illustrates an exploded cross-sectional side view of an exampleanode constructed from a porous current collector and alkali metal foil;

FIG. 3 illustrates an assembled cross-sectional side view of an exampleanode of FIG. 2 ;

FIG. 4 illustrates a cross-sectional side view of a current collectoropening and an extruded portion of alkali metal;

FIG. 5 illustrates another cross-sectional side view of a currentcollector opening and an extruded portion of alkali metal;

FIG. 6 is a flow-chart illustrating the steps of an example method offorming a porous current collector-alkali metal foil laminate for use asan anode in a secondary metal battery;

FIG. 7 shows an example roll-to-roll system for lamination of a carrierfilm and current collector metal foil;

FIG. 8 illustrates an example rotary kiss cut roll-to-roll system;

FIG. 9 illustrates an arrangement of openings in a porous currentcollector resulting from a multi-pass hole-forming process;

FIG. 10 is a flow-chart illustrating the steps of an example method forforming a porous current collector alkali metal foil laminate for use asan anode in a secondary metal battery;

FIGS. 11A-11F illustrates cross-sectional side views of examplestructures that may be formed during performance of the methodillustrated in FIG. 10 ;

FIG. 12 illustrates an example roll-to-roll system that may be used toautomate the method illustrated in FIG. 10 ;

FIG. 13 is an exploded side view of a first and second carrier film andcurrent collector metal foil;

FIG. 14 illustrates an example roll-to-roll system for forming a porouscurrent collector foil and first carrier film 1302 laminate;

FIGS. 15A-15G illustrate example hole pattern designs for use in porouscurrent collectors of the present disclosure;

FIG. 16 shows the cycling performance of cells made with the various 8um thick perforated copper foil designs having 40 um lithium foillaminated on one side;

FIG. 17 shows the cycling performance of cells made with the various 16um thick perforated copper foil designs having 40 um lithium foillaminated on one side;

FIGS. 18A-18C show an example perforated copper current collector;

FIGS. 19A-19D show example web patterns formed by a photo-lithographyprocess;

FIG. 20 shows the cycling performance of cells made with the variousperforated copper foil designs having 40 um lithium foil laminated onone side;

FIGS. 21A-21B show a porous titanium current collector made byphoto-etching process;

FIGS. 22A-C show computational simulations of lithium consumption nearthe web edge of a porous current collector in an anode for threedifferent web widths;

FIGS. 23A and 23B illustrate an example of a wide anode structure of thepresent disclosure with an alkali metal foil laminated to only one sideof a porous current collector;

FIG. 23C illustrates an example of a wide anode structure of the presentdisclosure with alkali metal foils laminated to both sides of a porouscurrent collector;

FIGS. 24A and 24B illustrate an example wide-format anode structure witha plurality of alkali metal foils laminated to only one side of a porouscurrent collector;

FIG. 24C illustrate an example wide-format anode structure with aplurality of alkali metal foils laminated to both sides of a porouscurrent collector;

FIG. 25 illustrates an example vapor deposition system for applying analkali metal to a current collector surface;

FIG. 26 illustrates an example electrodeposition system for applying analkali metal to a current collector surface;

FIG. 27 illustrates an example slot-die coating system for applying analkali metal to a current collector surface; and

FIG. 28 shows a diagrammatic representation of one embodiment of acomputing device for causing control systems to execute aspects of thepresent disclosure.

DETAILED DESCRIPTION

Aspects of the present disclosure include alkali metal secondarybatteries that include anodes constructed from alkali metal foil appliedto only one side of porous current collector metal foil. Openings in theporous current collectors permit alkali metal accessibility on bothsides of the anode structure, permitting efficient construction ofbatteries with multiple cathode-anode pairs. Such anode constructionsenable the utilization of lower-cost and more commonly available alkalimetal foil thickness, for example, thicknesses greater than or equal toapproximately 30 um, while still achieving high cell cycle life at asignificantly reduced cost. Such constructions also enable theproduction of cells with larger areal dimensions because thicker alkalifoils are available in wider widths, for example, widths greater than 55mm. Such constructions also increase electrical conductivity between thealkali metal foil and current collector, thereby leading to increasedhigh cell cycle life. Batteries with porous current collectors also haveincreased volumetric and gravimetric energy density.

Aspects of the present disclosure include methods of designing porouscurrent collectors, for example, to optimize the design of the currentcollector for a given application or performance metric, such asmaximized cell cycle life. One design variable is the hole pattern ofthe current collector, for example, selecting a hole pattern to maximizealkali metal access on both sides of the anode while providing goodelectrical contact between the current collector and alkali metal.Variables also include a shape of the holes, a size of the holes, anarrangement and spacing between the holes, a thickness of the currentcollector foil and an area percentage of the openings in the currentcollector foil.

FIG. 1 illustrates one example of a cell 102 of a secondary alkali metalbattery. FIG. 1 illustrates only some basic functional components ofcell 102. A real-world instantiation of the cell and/or battery willtypically be embodied using either a wound or stacked constructionincluding other components, such as electrical terminals, seal(s),thermal shutdown layer(s), and/or vent(s), among other things, that, forease of illustration, are not shown in FIG. 1 . In the illustratedexample, cell 102 includes a spaced-apart cathode 104 and anode 106, anda pair of corresponding respective current collectors 108, 110. A porousdielectric separator 112 is located between the cathode 104 and anode106 to electrically separate the cathode and anode but allow metal ions,such as lithium ions and ions of an electrolyte 114 to flowtherethrough. The porous dielectric separator 112 and/or one, the other,or both of cathode 104 and anode 106 may also be impregnated with theelectrolyte 114. The cell 102 includes a container 116 that contains thecomponents of the cell.

The cathode and anode 104, 106 may comprise a variety of differentstructures and materials compatible with lithium-metal ions andelectrolyte 114. Each of the current collectors 108, 110 may be made ofany suitable electrically conducting material, such as copper oraluminum, or any combination thereof. The porous dielectric separator112 may be made of any suitable porous dielectric material, such as aporous polymer, among others.

Cathode 104 includes a cathode material 118 that may be formed from avariety of materials known in the art such as a material of the generalformula of LixMyOz, where M is a transition metal such as Co, Mn, Ni, V,Fe, or Cr, and x, y, z are chosen to satisfy valence requirements. Inone or more embodiments, the cathode is a layered or spinel oxidematerial selected from the group comprising LiCoO₂,Li(Ni_(1/3)Mn_(1/3)Co_(1/3))O₂, Li(Ni_(0.86)Co_(0.5)Al_(0.05))O₂,LiMn₂O₄, Li(Mn_(1.5)Ni_(0.5))₂O₄, or their lithium rich versions. In oneor more embodiments, the cathode material is LiCoO₂ (charged to 4.4V vs.Li metal), NCA or NCM (622, 811) (charged to 4.30V vs. Li metal).

Anode 106 may include an anode material 120, such as a thin alkali metalfoil that, in the discharged state has a thickness in the range of 0um-1000 um, or 10 um-100 um, or 30 um-60 um, or 20 um-40 um. AlthoughFIG. 1 schematically shows anode material 120 adjacent current collector110, as described more below, the anode material, e.g., sheets or filmsof alkali metal, may be disposed on one or both sides of the currentcollector. In another example, cell 102 may initially only includecurrent collector 110 and alkali metal, e.g., lithium, initially storedin cathode 104 is deposited on the anode current collector 110 duringinitial cell charging to form anode 106. Further information regardingexample materials and constructions of cell 102 can be found in PCTpublication number WO 2017/214276, titled, “High energy density, highpower density, high capacity, and room temperature capable ‘anode-free’rechargeable batteries,” which is incorporated by reference herein inits entirety.

FIGS. 2 and 3 illustrate exploded and assembled cross-sectional sideviews, respectively, of an example anode 200 made in accordance with thepresent disclosure. Anode 200 includes a porous current collector 202having a thickness tCC extending between a first side 206 and anopposing second side 208 and a webbed structure defining a plurality ofopenings 210 (only one labeled) that extend from the first to the secondside. In some examples, thickness tCC may be between 1 um and 100 um andin some examples, between 4 um and 20 um. Anode 200 also includes analkali metal foil 204 having a thickness tMF. In some examples,thickness tMF may be between 1 um and 1,000 um, and in some examples,between 30 um and 60 um, and in some examples, greater than 20 um.Porous current collector 202 may be formed from any of a variety ofmaterials, such as copper, nickel, titanium, and other refractorymetals, and alloys that are stable against the corresponding alkalimetal, e.g., lithium. Alkali metal foil may also be formed from any of avariety of materials, such as lithium, sodium, potassium, etc.

As illustrated in FIG. 2 , anode 200 may be formed by applying alkalimetal foil 204 to only one side, for example, first side 206, of porouscurrent collector 202, by a variety of different processes describedherein. FIG. 3 illustrates anode 200 in an assembled form. As alkalimetal foil 204 was applied to first side 206, openings 210 of the porouscurrent collector 202 allowed portions of the alkali metal to flow orextrude through the openings. FIG. 3 conceptually shows assembled anode200 with a first portion 204 a of the alkali metal foil 204 located onthe first side 206 of the porous current collector, one or more secondportions 204 b located on the second side 208 of the current collectorand third portions 204 c of the alkali metal foil located in theopenings 210 of the current collector. First portion 204 a has athickness ta and second portion 204 b has a thickness tb, whereinta+tb≈tMF. As described more below, the relative sizes of ta and tb mayvary depending on the manufacturing technique used to assemble anode 200and the desired design construction. For example, in some cases, tb maybe approximately zero and alkali metal foil 204 may only be extrudedpartially through openings 210, or fully through the openings untilextruded portions of the alkali metal foil are substantially flush withsecond side 208 of current collector 202. In other examples, portions ofalkali metal foil 204 may be extruded beyond second side 208 such thatthey stand proud of the second side 208 and in some examples, theextruded portions may then be distributed across second side 208 of thecurrent collector, forming second portion 204 b of the alkali metal foil204. As will be appreciated, while FIG. 3 conceptually shows assembledanode 200 as having a substantially flat first side 302 and second side304, in some examples, second side 304 may have an undulating surfaceresulting from extruded portions of alkali metal foil 204 extending fromeach opening 210, and in some examples, the extruded portions are thendistributed across second side 208. As described more below, in someexamples, second side 208 may have a coating of alkali metal, such asthe same species of alkali metal as alkali metal foil 204 to improve theuniformity of alkali metal across second side 208.

FIGS. 4 and 5 illustrate a cross-sectional side view of just one opening210 of current collector 202 showing two example instantiations of anode200. In the example shown in FIG. 4 , alkali metal foil 204 has beenextruded through openings 210 until an end 402 of an extruded portion404 is substantially flush with second side 208 of current collector 202and the extruded portion 404 substantially fills the volume defined byopening 210. In the example shown in FIG. 4 , end 402 has a convexsurface with a local maxima of the convex surface flush or coplanar withsecond side 208 and the convex surface and the openings 210 defining asmall volume 406 of open space therebetween. FIG. 5 similarly shows anextruded portion 504 of the alkali metal foil 204 having an end 502 witha convex surface. In the example shown in FIG. 5 the alkali metal wasextruded farther through current collector 202 such that end 502 standsproud of and protrudes beyond second side 208. In some examples, end 502may be flattened so that the end of extruded portion 404 issubstantially flat and flush with second side 208. In some examples, theexample shown in FIG. 5 may provide higher battery cycle lifeperformance than the example shown in FIG. 4 due to higher electricalconductivity between the alkali metal and current collector. In otherexamples, second side 208 of current collector 202 may be placed on aflat surface and application of an extrusion process to the exampleshown in FIG. 4 can continue until end 402 flattens against the flatsurface and transitions from the convex shape shown in FIG. 4 to havinga flat or planar end with volume 406 being reduced or substantiallyeliminated.

FIG. 6 illustrates an example method 600 of forming a porous currentcollector-alkali metal foil laminate for use as an anode in a secondarymetal battery. At step 603, method 600 may include laminating a carrierfilm to a metal foil, such as a copper metal foil. Carrier film may beformed from a variety of materials, such as a polyester, such aspolyethylene terephthalate (PET), or any of a variety of other polymers,such as polyimide, polyethylene, polypropylene, polytetrafluoroethylene(PTFE), etc. Carrier film may also be formed from a variety of metals,such as copper, nickel, etc. In some examples, the thickness of thecarrier film is greater than the thickness of the current collector(tCC) and may have a thickness in the range of 1 um to 300 um, and insome examples, between 25 um and 250 um, and in some examples, greaterthan 4 um. The current collector metal foil may be attached to thecarrier film via a pressure sensitive or heat sensitive low-tackadhesive on the carrier film. In some examples, step 603 may includeactivating the carrier film, such as a PET carrier film, by a coronadischarge and then coating the carrier film with an adhesive shortlythereafter. In one example, the adhesive may be a low temperature, heatsealable, polyester resin dissolved in a solvent, such as Adcote 40-3Edissolved in ethyl acetate. In one example, the coating is done using anumber 8 wet film applicator rod, on the side of the carrier filmactivated by corona. The solvent is then removed by passing the filmthrough a drying tunnel maintained at 200° F. The metal foil, e.g., 8 umthick copper foil, may then be laminated to the carrier film on theadhesive-coated side. In one example, the lamination includes runningthe metal foil against a heated roller maintained at, for example, above180° F. during lamination. The lamination of the carrier film and metalfoil may be automated, as shown in the example roll-to-roll system 700illustrated in FIG. 7 . In the example shown in FIG. 7 , a roll 702 ofmetal foil 704 and a roll 706 of carrier film 708 may be fed through alaminating roller set 710 to laminate the two materials together. Thelaminating roller set may be heated to ensure good adhesion between themetal foil 704 and carrier film 708. The laminated metal/carrier 712 canbe guided by roller 714 and collected on roll 716. In other examples,instead of joining a carrier film and current collector foil vialamination, the current collector may be formed directly on the surfaceof the carrier film by a variety of processes, such aselectrodeposition, electroless plating, etc., and the current collectormay remain adhered to the carrier film, for example, by weak frictionaland/or electrostatic forces.

Referring again to FIG. 6 , at step 605, holes may be formed in thelaminated metal/carrier 712 using a hole forming process, such as aperforating process that uses an indexing mechanism to feed the laminatethrough the perforating head. In one example, the perforating head hastwo rows of pins that punch holes in the laminate as it moves throughthe tool. In one example, the metal foil being perforated is not undertension and is slack as it is fed through the perforating head. Thecarrier film is designed and configured to provide enough stiffness tothe metal foil so that it can be fed through the perforating tool. Thelaminate may be orientated so that the punch pin enters on the metalfoil side of the laminate and perforates both the metal and the carrierfilm. The carrier film also improves the quality of the holes formed inthe metal foil, resulting in substantially defect-free holes, whereasholes formed in thin metal foil without the carrier may be more likelyto include edge defects such as burrs, splinters, chads, and tears. Inone example, an un-punched solid band is left on the top and bottomedges of the roll for electrical tabs and ease of handling duringdownstream processes for preparing a final anode structure. The punchedholes may have any of a variety of diameters, center-to-centerdistances, and patterns. For example, a diameter in the range of 0.1 mmto 3.0 mm and in some examples 0.3 mm to 1.2 mm, a center-to-centerdistance of 0.15 mm to 3.5 mm and in some examples 0.4 mm to 1.4 mm, anda hexagonally arranged hole pattern.

In another example, at step 605, holes may be formed in the metal foilwith a rotary kiss cut method. FIG. 8 illustrates one example of arotary kiss cut roll-to-roll system 800 that includes a roll 802 ofmetal foil 804 and a roll 806 of carrier film 808 that may be fedthrough a rotary kiss-cut roller set 810. The rotary kiss-cut roller set810 is configured and dimensioned to form holes only in the metal foil804 and not the carrier film 808, with the resulting metal foilfragments (also referred to as chads) from the metal foil remainingattached to the low-tack adhesive side of the carrier film 808 when thenow-perforated metal foil 812 and carrier film 808 are delaminated orpeeled apart at roller set 814, with the metal chads remaining fixed tocarrier film 808, and perforated metal foil 812 collected on roller 816and carrier with chads collected on roller 818. In one example, athickness of metal foil 804 is less than 100 um, and in some examples,between 4 um and 20 um, and in some examples, approximately 8 um. Therotary kiss-cut roller set is configured to punch the metal foil 804while decreasing the chances the foil will tear or a crown will be lefton one side of a punched hole. In addition, the low tack on the carrierfilm 808 ensures the chads are removed along with the carrier filmthereby preventing the chads from remaining on the perforated metal foil812 and contaminating the later-formed anode.

As discussed more below, in some examples, it may be desirable toincrease an area of holes in a porous current collector relative to thetotal area of the current collector, also referred to herein as apercent open area. In a hole punching or rotary kiss-cut machine,however, there is a limit to how closely spaced the blades or pins canbe. FIG. 9 illustrates one example approach for increasing a percentopen area in a porous current collector with holes formed in anautomated hole punching or rotary kiss cut process despite minimum spacerequirements between adjacent pins or blades. FIG. 9 illustrates anarrangement of openings 900 in a porous current collector resulting froma multi-pass process, where a metal foil-carrier film laminate can bepassed through a series of hole punching or rotary kiss-cut roller setswhere each subsequent roller set is offset from adjacent roller sets.FIG. 9 shows an arrangement of openings 900 formed by a plurality ofoffset hole punch roller sets, with cross-hatching indicating the rollerset. In the illustrated example, four offset and in-series roller setshaving a standard and commercially available pin spacing are used tocreate four sets of openings 900 labeled 902, 904, 906, and 908 (onlyone opening from each set labeled). By way of non-limiting example, aminimum spacing between pins or blades of a standard rotary die may be0.8 mm, which would result in a maximum of ˜40% open area in a porousmetal foil. By controlling the registration of the metal foil,subsequent passes on the same foil through offset punch roller setshaving 0.8 mm spacing can result in greater than 60% open area with 0.2mm spacing between holes.

Referring again to FIG. 6 , at step 607, the carrier film can bedelaminated from the metal foil by peeling off the metal foil from thecarrier film. To prevent the metal foil from curling, substantially allof the peeling stress can be applied to the carrier film. This may bedone by keeping the now-perforated metal foil tensioned flat whilebending the carrier approximately 180° backwards in a sharp curl, whichmay be automated in a roll-to-roll converting machine. And at step 609the perforated metal foil can be used to build anodes for batteryapplication by laminating an alkali metal foil to one or both sides,covering the holes. Lamination may be done by a roll-mill process.During lamination, the roll mill or other lamination process may bedesigned and configured to apply a sufficient pressure to extrude thealkali metal foil through the openings in the porous metal foil suchthat the alkali metal nearly or completely fills the holes of theperforated foil (for example, as shown in FIGS. 4 and 5 ) to ensure goodelectrical contact between them. Discrete anode pieces can then bepunched out from the laminated ribbon and inspected for any edgedefects. The anodes can then be assembled together with cathodes,separator, and electrolyte to make batteries.

FIG. 10 illustrates another example method 1000 of forming a porouscurrent collector alkali metal foil laminate for use as an anode in asecondary metal battery, FIG. 11A-11F provide cross-sectional side viewsof example structures that may be formed during method 1000, and FIG. 12illustrates an example roll-to-roll system that may be used to automatemethod 1000. Referring first to FIG. 10 , at step 1003, a currentcollector metal foil may be laminated to at least one carrier film andat step 1005, holes may be formed in the current collector—carrier filmlaminate. FIG. 11A illustrates an example current collector metal foil1102, such as copper, and carrier film 1104, such as PET, laminatedtogether at a first side 1105 of the current collector foil 1102 to forma multi-layer substrate in the form of a carrier film-current collectorfoil laminate 1106. FIG. 11B illustrates one example where, at step 1005(FIG. 10 ), openings 1108 (only one labeled) are formed in both thecurrent collector foil 1102 and carrier film 1104, extending across theentire thickness of laminate 1106, forming a porous carrier film-currentcollector foil laminate 1107.

Returning to FIG. 10 , the example shown in FIGS. 11 and 12 does notinclude optional step 1007, which is discussed below. At step 1009 andreferring also to FIG. 11C, an alkali metal foil 1110 is laminated toonly one side of the porous current collector-carrier film laminate1107, here second side 1111 of the current collector, forming an alkalimetal foil-current collector foil-carrier film laminate 1112. Thelamination process at step 1009 is sufficient to cause the alkali metalfoil 1110 to flow or extrude through openings 1108 forming extrudedportions 1114 (only one labeled). In the illustrated example, thelamination process at step 1009 is sufficient to cause ends 1116 of theextruded portions 1114 to extend beyond first side 1105 of currentcollector foil 1102, and in the illustrated example, ends 1116 aresubstantially flush with a second side 1118 of carrier film 1104, thecarrier film having a first side 1120 opposite the second side 1118 thatis in contact with first side 1105 of the current collector foil 1102.

Carrier film 1104 can have any of a variety of thicknesses, tCF (FIG.11A). In some examples, thickness tCF of carrier film 1104 isselectively configured according to a desired extrusion depth ofextruded portions 1114 of alkali metal foil 1110. For example, for agiven thickness tMF of alkali metal foil, thickness tCF may be greaterthan or equal to tMF/2 so that a depth of alkali metal foil extrusionthrough carrier film 1104 can be approximately equal to a remainingthickness, ta (FIG. 11C) of the alkali metal foil on a second side 1111of current collector foil 1102. In some examples, tCF may be selected toobtain a target total volume of extruded portions 1114 that result in athickness of planarized extruded portions tPEP (FIG. 11F) beingapproximately equal to a remaining thickness, ta, of alkali metal foilon an opposite side of porous current collector 1102. In some examples,tCF may be selectively configured to obtain a target volume of extrudedportions 1114 that is approximately the same as a remaining volume ofthe alkali metal foil on second side 1111 of current collector 1102.

Referring to FIGS. 10 and 11D, at step 1011, method 1000 may includedelaminating carrier film 1104 from current collector foil 1102,resulting in an alkali metal foil-current collector metal foil laminate1122 that includes extruded portions 1114 of the alkali metal foil thatextend from and stand proud of first side 1105 of current collector foil1102. Referring to FIGS. 10, 11E, and 11F at optional step 1013, in someexamples, extruded portions 1114 of alkali metal may be planarizedacross first side 1105 of current collector foil 1102 by applying aforce 1130 (FIG. 11E) to the extruded portions, resulting in alkalimetal-current collector structure 1132 (FIG. 11F) that includes alkalimetal distributed across both the first and second sides 1111, 1105 ofthe porous current collector foil 1102 for use as an anode in asecondary metal battery. In other examples, step 1013 may be omitted.For example, extruded portions 1114 may be left in the protruding formshown in FIG. 11D. In such examples, a depth of extrusion may be lessthan a depth of extrusion when the planarizing step 1013 is performed.If step 1013 is omitted, an alternate step 1015 of applying alkali metalto first side 1105 may be performed to ensure a relatively uniform layerof alkali metal across the entire surface of first side 1105, includingthe spaces 1124 (FIG. 11D, only one labeled) between extruded portions1114. Any of a variety of processes may be used to apply alkali metal toside 1105, such as any of the processes described below in connectionwith FIGS. 25-27 , such as vapor deposition (FIG. 25 ),electrodeposition (FIG. 26 ), slot-die coating, dip coating, microgravure, or flexography (FIG. 27 ). Such additional process for applyinga layer of alkali metal to first side 1105 of current collector 1102 maybe performed after step 1011, or may be performed earlier, for example,before or after step 1003. In some examples, a thickness tCF of carrierfilm 1104 and resulting depth of extruded portions 1114 may be selectedto be substantially the same as a thickness of alkali metal coatingapplied at step 1015.

In yet other examples, a coating of alkali metal is not applied tospaces 1124 during the construction of the anode and instead step 1015is performed during initial charging of the battery cell by providing aninitial amount of alkali metal ions in cathodes 104 (FIG. 1 ) andplating the metal ions onto the spaces 1124 containing the bare currentcollector during the initial charging of the battery.

Referring again to FIG. 10 , a step 1017 that is substantially the sameas step 1015 may be performed after step 1013 to apply a layer of alkalimetal by, for example, vapor deposition, electrodeposition, slot-diecoating, or plating during an initial charging, before or afterplanarization of the extruded portions 1114. For example, afterplanarization at step 1013, the resulting alkali metal-current collectorstructure 1132 (FIG. 11F) may still include portions of bare currentcollector 1102 along first side 1105 that does not have a layer ofalkali metal. An additional layer of alkali metal may be applied toprovide a uniform coating of alkali metal along first side 1105.

Thus, by laminating alkali metal foil 1110 to current collector foil1102 while carrier foil 1104 is still laminated to the current collectormetal foil, extruded portions 1114 of the alkali metal foil can extendbeyond first side 1105 of the current collector foil 1102, providing avolume of alkali metal on first side 1105 of the current collector thatcan be planarized across the first side of the current collector,resulting in a more equal distribution of alkali metal on both the firstand second sides 1105, 1111, of the current collector.

FIG. 12 illustrates one example of a roll-to-roll system 1200 that maybe used to automate method 1000 and create the structures shown in FIGS.11A-11F. Example roll-to-roll system 1200 includes a roll 1202 ofcurrent collector foil 1102 and a roll 1206 of carrier film 1104, thatmay include any of the low-tack adhesives described herein for adheringto metal foil 1102, the foil 1102 and film 1104 may be fed through alaminating roller set 1210 to laminate the two materials together, andthe laminating roller set 1210 may be heated to ensure good adhesionbetween the current collector metal foil 1102 and carrier film 1104. Thecurrent collector metal foil/carrier film laminate 1106 (see also FIG.11A) can then be passed through a hole punching machine 1214 configuredto form openings 1108 (see also FIG. 11B) in the laminate 1106.

The now-porous current collector metal foil/carrier film laminate 1107may then be passed through a laminating roller set 1216 along with analkali metal foil 1110 from a roll 1218 of alkali metal foil, to formalkali metal foil-current collector foil-carrier film laminate 1112 (seealso FIG. 11C). Laminating roller set 1216 may be heated and may bedesigned, configured, and controlled to apply a sufficient pressure toachieve a desired volume and/or extrusion depth of extruded portions1114 of alkali metal (FIG. 11C), for example, a target height ofextruded portions relative to first side 1105 of current collector foil1102. In one example, system 1200 may include an extrusion monitoringsystem 1220 for monitoring an extent of extruded portions 1114 andprovide feedback to laminating roller set 1216 for controlling atemperature and/or applied pressure of the laminating roller set tocontrol an extent of extrusion. Extrusion monitoring system 1220 may beconfigured to generate an extrusion feedback signal 1221 according tothe determined extent of extrusion and configured to send the extrusionfeedback signal to laminating roller set 1216 to control an extent ofthe extrusion. Extrusion monitoring system 1220 may include any of avariety of sensing mechanisms known in the art for monitoring an extentof extrusion, such as a machine vision system configured to captureimages of alkali metal foil-current collector foil-carrier film laminate1112 which may be configured to capture and process images with amachine vision algorithm to determine if ends 1116 of extruded portionsare below, above, or substantially flush with second side 1118 ofcarrier 1104 (FIG. 11C). In some examples, extrusion monitoring system1220 may include one or more contact or non-contact sensors in additionto or instead of machine vision, for determining an extent of extrusion.

System 1200 also includes a porous carrier film roll 1222 fordelaminating porous carrier film 1224 from alkali metal foil-currentcollector metal foil laminate 1122 and collecting the porous carrierfilm 1224 for recycling or disposal. System 1200 also includes aplanarizing roller set 1226 that is designed and configured to applyheat and/or pressure to planarize extruded portions 1114 across firstside 1105 of current collector foil 1102. In one example, system 1200may include a planarizing monitoring system 1228 for monitoring anextent of planarization of extruded portions 1114 and provide feedbackto planarizing roller set 1226 for controlling a temperature or appliedpressure of the planarizing roller set to control planarization.Planarization monitoring system 1228 may be configured to generate aplanarization feedback signal 1229 according to the determined extent ofplanarization and configured to send the planarization feedback signalto planarizing roller set 1226 to control an extent of planarization.Planarizing monitoring system 1228 may include any of a variety ofsensing mechanisms known in the art for monitoring planarization, suchas a machine vision system configured to capture images of alkali metalfoil-current collector foil laminate 1132 which may be configured tocapture and process images with a machine vision algorithm to determineif extruded portions 1114 have been sufficiently planarized to cover allor substantially all of first side 1105 of current collector foil 1102.In some examples, planarizing monitoring system 1228 may include one ormore contact or non-contact sensors in addition to or instead of machinevision, for determining an extent of planarization. In some examples,system 1200 may include a multi-stage flat-press (not illustrated) whichmay be used instead of or in addition to laminating roller set 1216and/or planarizing roller set 1226.

Referring again to FIG. 10 as well as FIG. 13 , in some examples, atstep 1003 a plurality of carrier films are laminated to the currentcollector foil 1102. In the example shown in FIG. 13 , the plurality ofcarrier films include a first carrier film 1302 with a low-tack adhesivelayer 1303 and a second carrier film 1304 with a low tack adhesive layer1305, which, as described below, allows for a perforation of currentcollector foil 1102 and removal of resulting metal chads by delaminatingonly the second carrier film 1304 from the metal foil 1102 and firstcarrier film 1302 prior to lamination of an alkali metal foil to thecurrent collector. First and second carrier films 1302, 1304 can haveany of a variety of thicknesses. In some examples, they have the samethickness. In other examples, first carrier film 1302 can have athickness selectively configured according to a desired extrusion depthof alkali metal foil. For example, for a given thickness tMF of alkalimetal foil, first carrier film 1302 may have a thickness, tFCF that isgreater than or equal to tMF/2 so that a depth of alkali metal foilextrusion through the first carrier film can be approximately equal to aremaining thickness of the alkali metal film on an opposite side of thecurrent collector metal foil. In some examples, tFCF may be selected toobtain a target volume of extruded portions 1114 (FIG. 11C) that resultin a thickness of planarized extruded portions tPEP (FIG. 11F) beingapproximately equal to a remaining thickness, ta, of alkali metal foilon an opposite side of porous current collector 1102. A thickness, tSCF,of the second carrier film 1304 (FIG. 13 ) may be different thanthickness, tFCF, of first carrier film 1302, and may be greater than orequal to a minimum thickness for removing chads 1424 (FIG. 14 ) ofcurrent collector foil 1102 and first carrier film 1302 duringdelamination of the second carrier film as described below. In someexamples, thickness, tFCF, of first carrier film 1302 may be between 1um and 300 um, and in some examples, between 25 um and 250 um, and insome examples, greater than 4 um. In some examples, thickness, tSCF, ofsecond carrier film 1304 may be between 1 um and 500 um, and in someexamples, between 25 um and 250 um, and in some examples, greater than 4um.

Referring again to FIG. 10 , at steps 1005 and 1007, method 1000 mayinclude forming holes in the current collector metal foil/multi-carrierfilm laminate (step 1005) and then delaminating one of the carrier filmsto remove waste material. FIG. 14 illustrates an example roll-to-rollsystem 1400 for automatedly carrying out steps 1003 to 1007. As shown inFIG. 14 , system 1400 includes a current collector metal foil roll 1402for providing current collector foil 1102 and a first carrier film roll1404 for providing first carrier film 1302, which may be formed from anyof the materials described herein and have a low tack surface 1303 asany of the carrier films described herein. System 1400 includes alaminating roller set 1406 for performing a first portion of step 1003and laminating current collector foil 1102 and a first carrier film 1302to form a multi-layer substrate in the form of a current collector metalfoil-first carrier film laminate 1405. System 1400 also includes asecond carrier film roll 1408 for providing second carrier film 1304,and a laminating roller set 1410 for performing a second portion of step1003 and laminating the second carrier film 1304 to the currentcollector metal foil-first carrier film laminate 1405 to form amulti-layer substrate in the form of a current collector metalfoil-first carrier film-second carrier film laminate 1412. System 1400also includes a hole-forming roller set 1414 for performing step1005—forming holes in laminate 1412. In the illustrated example,hole-forming roller set 1414 is a rotary kiss-cut roller set havingcutting elements designed and configured to form holes that extend onlythrough current collector foil 1102 and first carrier film 1302 and notextend through second carrier film 1304, such that the resulting chads1424 of the current collector metal foil and first carrier film arepressed against and adhered to the second carrier film for removal.System 1400 also includes a roller set 1416, a roller 1418 forcollecting porous current collector foil and first carrier film 1302laminate 1420 for use for downstream steps, e.g., steps 1009-1017 (FIG.10 ), and a roller 1422 for collecting second carrier film 1304 andchads 1424 of current collector metal foil 1402 and first carrier film1302 formed by hole-forming roller set 1414. Roller set 1416 and rollers1418 and 1422 cooperate to perform step 1007—delaminating at least onecarrier film, e.g., second carrier film 1304, from current collectormetal foil/first carrier film laminate 1420. Thus system 1400 can beused instead of components 1202, 1206, 1210 and 1214 of system 1200 toprepare a porous current collector foil and first carrier film 1302laminate 1420 that may be laminated to an alkali metal foil, forexample, as described in connection with FIG. 12 and steps 1009-1017 ofFIG. 10 .

Porous Current Collector Design

The openings in a porous metal foil permits alkali metal accessibilityon both sides of a anode structure despite having been laminated to onlyone side of the current collector metal foil. The hole pattern on thecurrent collector metal foil can be optimized to allow for unhinderedalkali metal access on both sides of the anode, while providing goodelectrical contact, thereby increasing cell cycle life. Examplevariables that can be tuned to create an optimal hole design include 1)shape of the holes, 2) size of the holes, 3) arrangement and spacingbetween the holes, and 4) thickness of the porous foil. Shape, size, andspacing between the holes also determine a percentage of open area,i.e., the area of the current collector foil that is made up by theholes.

In one example, tests by the present inventors indicate an optimal holepattern includes round or polygon holes having a maximum width in therange of 0.1 mm to 3 mm and in some examples, 0.3 mm-1.5 mm, and in someexamples, 1 mm-1.5 mm, and in some examples, greater than approximately0.5 mm. The holes or openings may be placed in a close packedarrangement to give a percentage open area occupied by the openings inthe range of 30%-99% and in some examples, 40%-80%, and in someexamples, 60%-90%, and in some examples, above 50% and in some examples,greater than 80% based on a total area of 100% of the current collector,but not including any non-porous areas of the current collector, forexample, non-porous tabs or bands above or below the porous area thatmay be used for electrical tabs or ease of handling. A minimum strandwidth (also referred to as web width) of the resulting web is below 0.25mm and in some examples, below 0.15 mm. A thickness of the perforatedfoil may be between 4 to 20 um. An alkali metal may be applied to one orboth sides of the porous current collector using any of the methodsdisclosed herein, resulting in a thickness of alkali metal on each sideof the current collector in the range of 0 um-100 um, and in someexamples, 0 um-50 um.

FIGS. 15A-15G illustrate example hole pattern designs including varioushole shapes (Round, Hexagon) and sizes (0.3 mm, 0.75 mm, 1.2 mm). Theholes are arranged compactly in a triangular pitch and the spacingbetween the holes is tailored to get a desired open area percentage(40%, 55%, 70%, 80%). Holes punched on metal foils are traditionallyround (circular or oval) holes with no sharp corners for ease of toolmaintenance. Round holes, however, may form a perforation pattern havinguneven web widths (strand width) and limit how close the holes can bearranged. In comparison, polygon shaped holes (triangle, square,hexagon, etc.) offer a more compact arrangement with slimmer web widthsin the perforated pattern.

Table 1 (below) lists test results from example designs along with thecorresponding mass and thickness of anodes made by laminating 40 umthick lithium on one side of the perforated sample, wherein the lithiummetal substantially filled the openings in the porous current collector,but extrusions were not present on opposite side. Table 1 also lists thecycle life performance of cells made with the anode of this disclosurealong with that of the conventional Li/Cu/Li anode. As seen in Table 1,for the same total lithium thickness, anodes made with perforated copperfoil are lighter and thinner than that of a corresponding conventionalLi/Cu/Li anode. This reduction in mass and thickness of anode transfersto higher gravimetric and volumetric energy density of the cell. Ascopper can be denser than lithium, perforated foil with open area 70%and above reduces the mass of the anode by as much as 50% compared to aconventional Li/Cu/Li structure. Even if the perforated copper is 16 umthick, there may be a noticeable reduction in weight of more than 30%.Perforating the current collector also reduces the resulting anodethickness. As lithium is a soft metal, it extrudes under pressure duringlamination and fills the holes on the perforated foil, resulting inthinner anode. For instance, laminating 40 um lithium one side on to an8 um perforated foil with 70% open area results in an anode with athickness of 43 um, as opposed to 48 um (Table 1).

TABLE 1 After lamination Copper Hole size Web Open of 40 um lithium oneside thickness Hole diameter width hole Weight Thickness Cycle (micron)shape (mm) (mm) area (%) (g) (um) life 8 Round 0.3 0.151 40 0.118 46 850.085 55 0.099 45 93 0.75 0.213 55 0.096 45 92 1.2 0.165 70 0.078 43 100Hexagon 0.75 0.146 70 0.080 43 115 1.2 0.141 80 0.072 43 113 16 Round0.3 0.085 55 0.158 50 103 0.75 0.213 55 0.147 50 102 1.2 0.165 70 0.12247 113 Hexagon 0.75 0.146 70 0.125 47 118 1.2 0.141 80 0.098 46 123Traditional Li/Cu/Li 20/8/20 um 0.160 48 125

FIG. 16 shows the cycling performance of cells made with the various 8um thick perforated copper foil designs having 40 um lithium foillaminated on one side. The cycle performance of the cells tends toimprove with increase in hole size and open area. For example, of thecells with perforation design having round holes, the 1.2 mm size with70% open area shows the best cycle performance. In addition, cells withhexagon holes are found to show a comparatively better performance thanround holes.

FIG. 17 shows the cycling performance of cells made with the various 16um thick perforated copper foil designs having 40 um lithium foillaminated on one side. The cycle performance of cells with 16 umperforated copper can be better than the 8 um samples with similar holepattern. This could be due to a better electrical contact with thelaminated lithium (the thicker 16 um perforated copper is embeddeddeeper inside the lithium foil), which increases the lithium utilizationin the cell. Using copper foil with higher thickness (25 um or above)could negate any gravimetric and volumetric benefits of perforating,compared to conventional anode.

Similar to the 8 um samples, the 16 um samples also show cyclingperformance improvement with increase in hole size and open area. Cellswith hexagon holes were also found to show relatively better performancethan round holes. For instance, the cell design with 1.2 mm hexagonholes and 80% open area show cycling performance identical to that ofthe conventional Li/Cu/Li anode (FIG. 17 ).

The improvement in cell performance with hexagon holes could be due to athinner and uniform web width in the perforation pattern, that reducespolarization and promotes uniformity of lithium consumption in theanode. A compact hole arrangement and an unwavering web width in theperforation design, could also be attained with other polygon shapes,such as square, triangle, pentagon, etc. Table 1 also lists thecorresponding web widths for each hole pattern. Table 1 indicates theweb width of the perforation designs below 0.25 mm or below 0.15 mmresult in higher cycling performance.

As noted above, the test data shown in Table 1 and FIGS. 16 and 17 arefrom an anode with alkali metal that substantially filled the openingsin the porous current collector, but extrusions of alkali metal were notpresent. In such a configuration, it may be more important to maximizethe percent open area of the current collector to increase alkali metalutilization. By contrast, for anodes constructed with the variousmethods discussed in connection with FIG. 10 , high cycling performancemay be achievable with a porous current collector with a lower percentopen area because the extruded portions of the alkali metal enable agreater distribution of the alkali metal on both sides of the currentcollector, resulting in improved electrical contact and increased alkalimetal utilization. Thus, a method of designing a porous currentcollector may include a step of determining the amount of alkali metalthat will be located on both sides of the current collector, and thendetermining a corresponding minimum % open area of the current collectorto achieve a target cell performance metric, such as cell cycle life.

Referring again to FIGS. 4 and 5 , the extent of lamination betweenperforated current collector 202 and alkali metal foil 204 isschematically shown. During lamination, the applied pressure andtemperature influences the degree to which the alkali metal extrudes andfills or nearly fills openings 210 of the porous current collector 202.Testing by the present inventors indicate that, in some examples, agreater extent of alkali metal extrusion and filling of the openings 210with the alkali metal improves cell cycling performance, which may bedue to improving electrical contact between the alkali metal and currentcollector. Alkali metal foil 204 that extrudes inside openings 210 mayhave an end 402 having a convex surface, which can either be on levelwith the current collector surface or may protrude to some extent.

In some examples, a porous current collector may be made via aphoto-lithography process by electroforming or photo-etching. Suchprocesses may allow for production of perforated metal foil having highopen area, together with thinner and uniform web widths as compared to ahole punching process. In general, a photo-lithography process enablesproduction of perforated foil having open area as high as 90% or more.The high open area permits uniform alkali metal accessibility on bothsides of the anode laminate built with alkali metal foil on one side.Photo-lithography processes allow for production of porous metal foilwith almost any hole shape. For instance, any polygon-shaped hole(triangle, square, pentagon, hexagon, etc.) can be made. In comparisonto round or oval hole pattern, the polygons can be arranged morecompactly to achieve higher open area and uniform web width.Photo-lithography processes allow for production of perforated patternswith much more narrow web widths than round holes. For example, theminimum spacing between the holes may be below 0.2 mm, which is atypical minimum spacing required for conventional hole punchingprocesses, and could be as low as, for example, 0.05 mm. Narrow webwidths, in general, allow for perforation designs with higher open areaand greater alkali metal accessibility.

Photo-lithography is a standard technique used in manufacturing partsfor micro-electronics. In the photo-etching process a photo-resist iscoated on a substrate and a subsequent image is exposed. The workpieceis developed to remove unexposed resist and the exposed resist is usedto mask the regions on the surface of a thin foil that corresponds tothe web pattern. The work piece is then exposed to a metal-selectiveetchant to etch away the metal not covered by the photoresist. In asubsequent step the remaining photoresist is then removed leaving thepatterned workpiece. In the electroforming process, a mask is applied ona mandrel in regions corresponding to holes in a web, and the currentcollector foil is electro-deposited in the gaps, to make the web.

FIGS. 18A and 18B show a perforated copper current collector made byelectroforming, with an open area of 80%, formed by a close arrangementof hexagon-shaped holes. In comparison, round holes of the same size andarrangement as shown in FIG. 18C results in a 72% open area. FIGS. 18Band 18C show the web patterns formed by the hexagon and the round holes.As evident from the images, the web width between the hexagons is muchthinner and uniform than the round holes, allowing for high open area.

FIGS. 19A-20 and Table 2 illustrate a subset of the test anodesdescribed above in connection with FIG. 1 to highlight the impact ofhole shape on web width and percent open area. FIGS. 19A-19D showexample web patterns formed by a photo-lithography process, includinground and hexagon-shaped holes of size 0.75 mm and 1.2 mm, and open areabetween 55% and 80%. Table 2 lists the web widths of hole patterns aboveand the corresponding cycle life attained in cells (FIG. 20 ) made withanodes having perforated copper current collector of that pattern. Thecycling performance of cells is directly proportional to the percentageopen area and inversely proportional to the web width of the perforationpattern. The anodes used for the test data shown in Table 2 and FIG. 20were made using step 609 of process 600 (FIG. 6 ) wherein the lithiummetal substantially filled the openings in the porous current collector,but extrusions were not present on opposite side. Table 2 lists the webwidths of the hole patterns illustrated in FIGS. 19A-19D and thecorresponding cycle life measured in tests of cells that incorporatedthe illustrated current collectors. FIG. 20 illustrates cycle lifeperformance data listed in Table 2. Table 2 and FIG. 20 indicate thecycling performance of cells is directly proportional to the percentageopen area and inversely proportional to the web width of the perforationpattern. As noted above in connection with Table 1 and FIGS. 16 and 17 ,cycling performance for the smaller % open area current collectors canbe increased by using method 1000 (FIG. 10 ) for construction of theanode.

TABLE 2 Cycle life Hole size Web Open with 40 um Hole diameter widthhole area lithium on shape (mm) (mm) (%) one side Round 0.75 0.213 55 921.2 0.165 70 100 Hexagon 0.75 0.146 70 115 1.2 0.141 80 113

FIGS. 21A-21B shows a porous titanium current collector made byphoto-etching process, with ˜90% open area. The high open area attainedis a result of the closely packed square holes with a web width of 0.05mm, made possible by the photo-etching process.

FIGS. 22A-22C show computational simulations of lithium consumption nearweb edge in an anode for three different web widths of 0.1 mm (FIG.22A), 0.2 mm (FIG. 22B), and 0.3 mm (FIG. 22C) simulating lithiumconsumption with time adjacent the web edge during cycling in cellsbuilt with anode having perforated current collector and laminatedlithium on one side using method 600 (FIG. 6 ) wherein the lithium metalsubstantially filled the openings in the porous current collector, butextrusions were not present on the porous current collector side. On theside of the anode with porous current collector, the width of the web isshown to affect the uniformity of lithium consumption. In essence, thethinner the web width, the more uniform the lithium consumption, whichleads to better lithium utilization and longer cycle life of thebattery.

The present disclosure includes a variety of constructions and methodsof manufacture that include the manufacture and use of a perforatedmetal foil as a current collector and the lamination of an alkali metalfoil to only one side of the perforated foil to produce an anode. Theopenings in the current collector foil permit alkali metal accessibilityon both sides of the anode structure. These methods enable theutilization of more commonly available alkali metal foils, such aslithium foils, for example, foils with a thickness greater than or equalto 30 um, for anode production, with substantially the same resultinganode thickness as compared to the conventional approach of applying athinner alkali metal foil to both sides of a current collector. Fornon-limiting example, a 40 um thick lithium foil may be laminated toonly one side of an 8 um perforated copper foil to make an anode, theresulting thickness of which is similar to or lower than a conventionalLi/Cu/Li anode with 20/8/20 um thicknesses. Such methods also enable theproduction of battery cells with larger areal dimensions as it makes useof more commonly available and easily manufactured alkali metal foils ofthickness 30 um or above that is also available in wider roll widths(for example, up to 200 mm). The anodes of this disclosure also increasethe gravimetric and volumetric energy density of the cell, as theopenings in the current collector reduce the mass and volume associatedwith the typically dense current collector foil.

By way of example, in a prior art secondary lithium batterymanufacturing process, lithium foil (active material) is laminated toboth sides of a copper foil (current collector) to form the conventional(Li/Cu/Li) anode. For example, a ˜20 um thick lithium foil is laminatedto both sides of an ˜8 um copper foil. However, as lithium can be softand sticky, it may be difficult by traditional roll-milling process toproduce lithium foil with thickness ˜25 um or below. By contrast, usingone or more of the methods disclosed herein, a perforated foil can beused as the current collector and lithium can be laminated to only oneside of the perforated foil. The perforations on the current collectorallow for the lithium to be accessed on both sides of the anodestructure. This disclosure enables use of the commonly available lithiumfoil of thickness 30 um or above, for anode fabrication. For example, a40 um thick lithium foil laminated to one side of a perforated copperfoil, could be used as the anode.

In one non-limiting example, a perforated copper foil is made via one ofthe methods disclosed herein. The width of the roll of perforatedcurrent collector foil may be above 60 mm or 70 mm. The percentage openarea of the perforated foil may be above 40% or 60%. An un-punched solidband can be left on the top and bottom edges of the roll for electricalcontact and ease of handling. The thickness of the perforated copperfoil may be between 4 um to 20 um. The perforated copper is thenlaminated with a lithium foil on only one side, covering the holes, tomake anodes for a battery application. The width of the lithium foil maybe substantially the same or slightly wider than the perforated part ofthe copper foil. The thickness of the lithium foil may be between 30 umand 60 um. In one example, an 8 um thick perforated copper foil with awidth of a perforated strip or area that is approximately 75 mm and 65%open area may be used. The perforated copper foil is laminated with a 77mm wide, 40 um thick lithium foil on one side, covering the holes.Lamination may be done with any of the methods and systems disclosedherein, for example, using a roll-mill process, in which, the pressureof the roll-mill is set such that lithium extrudes and nearly orcompletely fills the holes of the perforated copper to ensure goodelectrical contact and high lithium accessibility on the copper side.

Discrete anode pieces can then be punched out from the laminatedcopper-lithium ribbon and inspected for any edge defects. The anodes arethen assembled together with cathode, separator, and electrolyte to makelithium batteries. The perforated copper enables anodes with single-sidelithium lamination, as the perforations allow the lithium to be accessedon both sides of the electrode. As copper can be much denser thanlithium, the perforated copper also lowers the anode mass significantlyand boost the specific energy of the battery.

Photo-lithography processes enable production of discrete currentcollector parts with customized size and hole patterns having high openarea. By way of example, a ˜90 mm wide perforated titanium currentcollector made by a photo-etching process, with ˜90% open area may beconstructed. In comparison to a 60 mm wide conventional lithium anode,anodes with perforated current collectors allow cell production withmuch larger areal dimensions. Pouch cells made with 90 mm wide anode aretypically 3 to 4 times larger than cells made with conventional anodes.Thus, perforated current collectors with lithium laminated to one sideallows for more flexible cell sizes, and higher packing and energydensity at the pack level.

Perforated current collectors of this disclosure may be made with anymetal suitable for an alkali metal cell, such as copper, titanium,nickel and other refractory metals and alloys that are stable against agiven alkali metal, e.g. lithium. Perforated current collectors of thepresent disclosure may be made by any of a variety of processes, such asmanual hole punching, rotary die-cutting, electroforming, photo-etching,laser cutting, etc. A perforated current collector may also be made byflattening a woven, non-woven, or an expanded metal mesh that may beformed in a metal mesh weaving or forming process. In some examples, aperforated current collector of this disclosure may have thicknessranging from 4 to 20 um or above. The perforated current collectors ofthis disclosure could also be used in cells that have alkali metalsother than lithium as anode active material, such as, sodium, potassium,etc.

FIGS. 23A and 23B illustrate an example wide anode 2300 of the presentdisclosure that includes an alkali metal foil 2302 laminated to only oneside 2304 of a porous current collector 2306 with a plurality ofopenings 2308 (only one labeled). By laminating alkali metal foil 2302to only one side, a thicker alkali metal foil can be used, while stillresulting in a lower total thickness for the anode. By utilizing aporous current collector 2306, openings 2308 allow for access to alkalimetal 2302 from the second side 2314 of the current collector. FIG. 23Cillustrates a cross section of a second example of a wide anode 2310that is the same as anode 2300 except anode 2310 includes a secondalkali metal foil 2312 laminated to a second side 2314 of currentcollector 2306. In other examples, anode 2300 or 2310 may have a solidnon-porous current collector that does not include openings 2308. Asshown in FIGS. 23B and 23C, alkali metal foils 2302 and 2312 may have athickness from 0 um to 1000 um and a width from 55 mm to 300 mm orgreater. Such anode structures allow for the production of secondaryalkali metal batteries with large cell dimensions which may be used tomeet the energy demands of various applications, including consumerelectronic, commercial/recreational drone, and electric vehicleapplications.

FIGS. 24A and 24B illustrate an example wide-format anode 2400 withlithium width between 55 to 300 mm or greater formed by parallellamination of multiple lithium ribbons 2402, 2404, each with widthbelow, for example, 55 mm. For example, to make an 80 mm wide lithiumanode 2400, two lithium ribbons 2402, 2404 of width 50 mm and 30 mm,respectively, can be laminated side-by-side to a first side 2406 of aporous current collector foil 2408 in a closely-spaced parallelarrangement across the porous current collector foil to form awide-format anode. A gap 2410 between the laminated lithium ribbons2402, 2404 may be small, for example, less than 0.5 mm to maximizeuniform alkali metal availability to an adjacent cathode. FIG. 24C showsan example anode 2420 that is the same as anode 2400 except that twolithium ribbons 2422 and 2424 are also laminated to second side 2426 ofcurrent collector 2408. In other examples, anode 2400 or 2420 may beformed with a solid non-porous current collector that does not includeopenings.

Anode structure with a thin alkali metal layer, e.g., a thickness below30 um and large widths, e.g., between 55 mm to 800 mm or greater may bemanufactured via vapor deposition of alkali metal on a current collectormetal substrate in a roll-to-roll process as illustrated in FIG. 25 . Asshown, alkali metal may be melted in a crucible 2502 under partialpressure or inert atmosphere, and the vapor 2504 deposited on thecurrent collector foil 2506 held above the crucible. Alkali metal vaporsolidifies upon deposition on the current collector substrate and insome examples, the process is repeated on the other side of the currentcollector foil. A thickness of deposited alkali metal is determined bythe duration of exposure to the vapor (roll speed) and a width of thedeposited alkali metal is determined by the size of the crucible openingto the substrate.

Anode structure with a thin alkali metal layer, e.g., a thickness below30 um and large widths, e.g., between 55 mm to 800 mm or greater mayalso be made by electrodeposition of alkali metal on current collectorsubstrate in a roll-to-roll process as shown in FIG. 26 .Electrodeposition of alkali metal on a current collector foil substrate2602 may be done in an electrochemical cell 2604 containing alkali metal2606 as the positive electrode, current collector foil substrate 2602 asthe negative electrode, and an alkali metal-ion conducting electrolyte2608. Alkali metal-ion conducting electrolyte 2608 could be made, forexample, by dissolving an alkali metal salt in non-aqueous solvent. Athickness of the deposited alkali metal on the current collector foilsubstrate 2602 is determined by the current density and duration ofexposure to the electrolyte, and a width of the alkali metal depositedis determined by the width of the current collector substrate exposed tothe electrolyte.

Anode structure with a thin alkali metal layer, e.g., a thickness below30 um and large widths, e.g., between 55 mm to 800 mm or greater mayalso be made by coating molten alkali metal on a current collectorsubstrate. Molten alkali metal 2702 can be coated on the currentcollector foil substrate 2704 via several roll-to-roll processes, suchas, slot-die coating, dip coating, micro gravure, and flexography. FIG.27 shows a schematic of slot-die coating of molten alkali metal on acurrent collector substrate. In the illustrated process, molten alkalimetal 2702, e.g., lithium, is injected through a slot-die head 2706 andcoated on one side of a current collector foil substrate 2704. Alkalimetal solidifies upon coating on the substrate and the process may berepeated on the other side of the current collector foil. The thicknessof the coated alkali metal on the current collector substrate isdetermined by the injection pressure & roll speed and the width of thealkali metal coated is determined by the slot-die head.

As noted above, in examples where an alkali metal foil is laminated toonly one first side of a porous current collector, the second oppositeside of the porous current collector may be coated with the alkali metalusing any coating process known in the art, including any of the coatingprocesses described and illustrated in connection with FIGS. 25-27 , forexample, during steps 1015 and/or 1017 (FIG. 10 ). In other examples,alkali metal foil can be laminated to both sides of any of the porouscurrent collectors disclosed herein.

Any one or more of the aspects and embodiments described herein may beconveniently implemented using one or more machines (e.g., one or morecomputing devices that are utilized as a user computing device for anelectronic document, one or more server devices, such as a documentserver, etc.) programmed according to the teachings of the presentspecification, as will be apparent to those of ordinary skill in thecomputer art. Appropriate software coding can readily be prepared byskilled programmers based on the teachings of the present disclosure, aswill be apparent to those of ordinary skill in the software art. Aspectsand implementations discussed above employing software and/or softwaremodules may also include appropriate hardware for assisting in theimplementation of the machine executable instructions of the softwareand/or software module.

Such software may be a computer program product that employs amachine-readable storage medium. A machine-readable storage medium maybe any medium that is capable of storing and/or encoding a sequence ofinstructions for execution by a machine (e.g., a computing device) andthat causes the machine to perform any one of the methodologies and/orembodiments described herein. Examples of a machine-readable storagemedium include, but are not limited to, a magnetic disk, an optical disc(e.g., CD, CD-R, DVD, DVD-R, etc.), a magneto-optical disk, a read-onlymemory “ROM” device, a random access memory “RAM” device, a magneticcard, an optical card, a solid-state memory device, an EPROM, an EEPROM,and any combinations thereof. A machine-readable medium, as used herein,is intended to include a single medium as well as a collection ofphysically separate media, such as, for example, a collection of compactdiscs or one or more hard disk drives in combination with a computermemory. As used herein, a machine-readable storage medium does notinclude transitory forms of signal transmission.

Such software may also include information (e.g., data) carried as adata signal on a data carrier, such as a carrier wave. For example,machine-executable information may be included as a data-carrying signalembodied in a data carrier in which the signal encodes a sequence ofinstruction, or portion thereof, for execution by a machine (e.g., acomputing device) and any related information (e.g., data structures anddata) that causes the machine to perform any one of the methodologiesand/or embodiments described herein.

Examples of a computing device include, but are not limited to, anelectronic book reading device, a computer workstation, a terminalcomputer, a server computer, a handheld device (e.g., a tablet computer,a smartphone, etc.), a web appliance, a network router, a networkswitch, a network bridge, any machine capable of executing a sequence ofinstructions that specify an action to be taken by that machine, and anycombinations thereof. In one example, a computing device may includeand/or be included in a kiosk.

FIG. 28 shows a diagrammatic representation of one embodiment of acomputing device in the exemplary form of a computer system 2800 withinwhich a set of instructions for causing a control system, such as theroll-to-roll system 1200 system of FIG. 12 , to perform any one or moreof the aspects and/or methodologies of the present disclosure may beexecuted. It is also contemplated that multiple computing devices may beutilized to implement a specially configured set of instructions forcausing one or more of the devices to perform any one or more of theaspects and/or methodologies of the present disclosure. Computer system2800 includes a processor 2804 and a memory 2808 that communicate witheach other, and with other components, via a bus 2812. Bus 2812 mayinclude any of several types of bus structures including, but notlimited to, a memory bus, a memory controller, a peripheral bus, a localbus, and any combinations thereof, using any of a variety of busarchitectures.

Memory 2808 may include various components (e.g., machine-readablemedia) including, but not limited to, a random access memory component,a read only component, and any combinations thereof. In one example, abasic input/output system 2816 (BIOS), including basic routines thathelp to transfer information between elements within computer system2800, such as during start-up, may be stored in memory 2808. Memory 2808may also include (e.g., stored on one or more machine-readable media)instructions (e.g., software) 2820 embodying any one or more of theaspects and/or methodologies of the present disclosure. In anotherexample, memory 2808 may further include any number of program modulesincluding, but not limited to, an operating system, one or moreapplication programs, other program modules, program data, and anycombinations thereof.

Computer system 2800 may also include a storage device 2824. Examples ofa storage device (e.g., storage device 2824) include, but are notlimited to, a hard disk drive, a magnetic disk drive, an optical discdrive in combination with an optical medium, a solid-state memorydevice, and any combinations thereof. Storage device 2824 may beconnected to bus 2812 by an appropriate interface (not shown). Exampleinterfaces include, but are not limited to, SCSI, advanced technologyattachment (ATA), serial ATA, universal serial bus (USB), IEEE 1394(FIREWIRE), and any combinations thereof. In one example, storage device2824 (or one or more components thereof) may be removably interfacedwith computer system 2800 (e.g., via an external port connector (notshown)). Particularly, storage device 2824 and an associatedmachine-readable medium 2828 may provide nonvolatile and/or volatilestorage of machine-readable instructions, data structures, programmodules, and/or other data for computer system 2800. In one example,software 2820 may reside, completely or partially, withinmachine-readable medium 2828. In another example, software 2820 mayreside, completely or partially, within processor 2804.

Computer system 2800 may also include an input device 2832. In oneexample, a user of computer system 2800 may enter commands and/or otherinformation into computer system 2800 via input device 2832. Examples ofan input device 2832 include, but are not limited to, an alpha-numericinput device (e.g., a keyboard), a pointing device, a joystick, agamepad, an audio input device (e.g., a microphone, a voice responsesystem, etc.), a cursor control device (e.g., a mouse), a touchpad, anoptical scanner, a video capture device (e.g., a still camera, a videocamera), a touchscreen, and any combinations thereof. Input device 2832may be interfaced to bus 2812 via any of a variety of interfaces (notshown) including, but not limited to, a serial interface, a parallelinterface, a game port, a USB interface, a FIREWIRE interface, a directinterface to bus 2812, and any combinations thereof. Input device 2832may include a touch screen interface that may be a part of or separatefrom display 2836, discussed further below. Input device 2832 may beutilized as a user selection device for selecting one or more graphicalrepresentations in a graphical interface as described above.

A user may also input commands and/or other information to computersystem 2800 via storage device 2824 (e.g., a removable disk drive, aflash drive, etc.) and/or network interface device 2840. A networkinterface device, such as network interface device 2840, may be utilizedfor connecting computer system 2800 to one or more of a variety ofnetworks, such as network 2844, and one or more remote devices 2848connected thereto. Examples of a network interface device include, butare not limited to, a network interface card (e.g., a mobile networkinterface card, a LAN card), a modem, and any combination thereof.Examples of a network include, but are not limited to, a wide areanetwork (e.g., the Internet, an enterprise network), a local areanetwork (e.g., a network associated with an office, a building, a campusor other relatively small geographic space), a telephone network, a datanetwork associated with a telephone/voice provider (e.g., a mobilecommunications provider data and/or voice network), a direct connectionbetween two computing devices, and any combinations thereof. A network,such as network 2844, may employ a wired and/or a wireless mode ofcommunication. In general, any network topology may be used. Information(e.g., data, software 2820, etc.) may be communicated to and/or fromcomputer system 2800 via network interface device 2840.

Computer system 2800 may further include a video display adapter 2852for communicating a displayable image to a display device, such asdisplay device 2836. Examples of a display device include, but are notlimited to, a liquid crystal display (LCD), a cathode ray tube (CRT), aplasma display, a light emitting diode (LED) display, and anycombinations thereof. Display adapter 2852 and display device 2836 maybe utilized in combination with processor 2804 to provide graphicalrepresentations of aspects of the present disclosure. In addition to adisplay device, computer system 2800 may include one or more otherperipheral output devices including, but not limited to, an audiospeaker, a printer, and any combinations thereof. Such peripheral outputdevices may be connected to bus 2812 via a peripheral interface 2856.Examples of a peripheral interface include, but are not limited to, aserial port, a USB connection, a FIREWIRE connection, a parallelconnection, and any combinations thereof.

The foregoing has been a detailed description of illustrativeembodiments of the disclosure. It is noted that in the presentspecification and claims appended hereto, conjunctive language such asis used in the phrases “at least one of X, Y and Z” and “one or more ofX, Y, and Z,” unless specifically stated or indicated otherwise, shallbe taken to mean that each item in the conjunctive list can be presentin any number exclusive of every other item in the list or in any numberin combination with any or all other item(s) in the conjunctive list,each of which may also be present in any number. Applying this generalrule, the conjunctive phrases in the foregoing examples in which theconjunctive list consists of X, Y, and Z shall each encompass: one ormore of X; one or more of Y; one or more of Z; one or more of X and oneor more of Y; one or more of Y and one or more of Z; one or more of Xand one or more of Z; and one or more of X, one or more of Y and one ormore of Z.

Various modifications and additions can be made without departing fromthe spirit and scope of this disclosure. Features of each of the variousembodiments described above may be combined with features of otherdescribed embodiments as appropriate in order to provide a multiplicityof feature combinations in associated new embodiments. Furthermore,while the foregoing describes a number of separate embodiments, what hasbeen described herein is merely illustrative of the application of theprinciples of the present disclosure. Additionally, although particularmethods herein may be illustrated and/or described as being performed ina specific order, the ordering is highly variable within ordinary skillto achieve aspects of the present disclosure. Accordingly, thisdescription is meant to be taken only by way of example, and not tootherwise limit the scope of this disclosure.

What is claimed is:
 1. An anode for an alkali metal secondary battery,comprising: a porous current collector foil having first and secondopposing sides and a webbed structure defining openings each having avolume; and an alkali metal foil laminated to one side of the porouscurrent collector foil, wherein portions of the alkali metal foil extendthrough the openings from the first opposing side to the second opposingside and substantially fill the volumes of the openings.
 2. The anode ofclaim 1, wherein the alkali metal foil is laminated on the firstopposing side and the second opposing side includes a continuous layerof alkali metal formed from the portions of the alkali metal foil thatextruded through the openings.
 3. The anode of claim 1, wherein thealkali metal foil is laminated on the first opposing side, and theportions of the alkali metal foil present in the openings is flush withthe second opposing side.
 4. The anode of claim 3, further comprising asecond alkali metal laminated onto the second opposing side.
 5. Theanode of claim 3, wherein the alkali metal foil comprises an alkalimetal, and the anode further comprising an alkali metal coating appliedto the second opposing side, wherein the alkali metal coating is made ofthe alkali metal.
 6. The anode of claim 1, wherein the openings in theporous current collector foil include a plurality of identically sizedpolygonal openings arranged with one another so as to define uniform webwidths within the porous current collector foil between adjacent one ofthe identically sized polygonal openings.
 7. The anode of claim 6,wherein the identically sized polygonal openings are hexagonal in shape.8. The anode of claim 6, wherein the openings in the porous currentcollector foil define a percent open area that is greater than 80%. 9.The anode of claim 1, wherein the porous current collector foil has athickness in a range of 4 μm to 20 μm.
 10. The anode of claim 1, whereinthe openings in the porous current collector foil define a percent openarea that is greater than 40%.
 11. The anode of claim 1, wherein theopenings in the porous current collector foil define a percent open areathat is greater than 60%.
 12. The anode of claim 1, wherein the openingsin the porous current collector foil define a percent open area that isgreater than 80%.
 13. The anode of claim 1, wherein the openings have awidth that is greater than 0.5 mm.
 14. The anode of claim 1, wherein theopenings have a maximum width that is greater than 0.75 mm.
 15. Theanode of claim 1, wherein the openings have a maximum width that isgreater than 1.2 mm.
 16. The anode of claim 1, wherein the webbedstructure of the porous current collector has a minimum web widthextending between adjacent ones of the openings, wherein the minimum webwidth is less than 1 mm.
 17. The anode of claim 1, wherein the webbedstructure of the porous current collector has a minimum web widthextending between adjacent ones of the openings, wherein the minimum webwidth is less than 0.25 mm.
 18. The anode of claim 1, wherein the webbedstructure of the porous current collector has a minimum web widthextending between adjacent ones of the openings, wherein the minimum webwidth is less than 0.15 mm.
 19. The anode of claim 1, wherein theopenings in the porous current collector foil define a percent open areathat is greater than 75% and have a minimum spacing of less than 0.2 mm.20. The anode of claim 1, wherein the openings in the porous currentcollector foil define a percent open area that is greater than 75%, havea size greater than 1.2 mm, and have a minimum spacing of less than 0.2mm.
 21. The anode of claim 1, wherein the openings in the porous currentcollector foil are polygonal in shape, define a percent open area thatis greater than 75%, have a size greater than 1.2 mm, and have a minimumspacing of less than 0.2 mm.
 22. The anode of claim 1, wherein theopenings in the porous current collector foil are polygonal in shape,define a percent open area that is greater than 75%, and have a minimumspacing of less than 0.2 mm.
 23. The anode of claim 1, wherein theopenings in the porous current collector foil are polygonal in shape andhave a minimum spacing of less than 0.2 mm.
 24. The anode of claim 1,wherein the alkali metal foil has a width that is greater than 55 mm.25. The anode of claim 1, wherein the anode includes a plurality of rowsof the alkali metal foil positioned in a closely-spaced parallelarrangement across the porous current collector foil, wherein a width ofthe anode is 55 mm or more.
 26. The anode of claim 25, wherein thealkali metal foil is lithium metal foil having a thickness of 100 μm orless.
 27. The anode of claim 25, wherein the alkali metal foil islithium metal foil having a thickness of 40 μm or less.
 28. The anode ofclaim 1, wherein the alkali metal foil is lithium metal foil having athickness of 100 μm or less.
 29. The anode of claim 1, wherein thealkali metal foil is lithium metal foil having a thickness of 40 μm orless.
 30. A secondary battery, comprising: an alkali metal anode, acathode, and a separator; wherein the alkali metal anode is an anodeaccording to any one of claims 1-29.